Yarn-guiding traverse drum



Dec? 1967 I I KOICHIRO KUBO ETAL 3,356,308

YARN- GUIDING TRAVERSE DRUM Filed April 27, 1966 lNVENTOR ATTORNEY United States Patent l 3,356,308 YARN-GUIDING TRAVERSE DRUM Koichiro Kubo, Sakyo-ku, Kyoto, Junji Takematu, Fushimi-ku, Kyoto, and Jim Yamakawa, Kameoka, Kyoto, Japan, assignors to Shimadzu Seisakusho LtdL, Nakagyo-ku, Kyoto, Japan, a corporation of Ja an p Filed Apr. 27, 1966, Ser. No. 545,651

Claims priority, application Japan, Apr. 28, 1965,

2 Claims. (Cl. 242-431) This invention relates to a traverse mechanism in winding machines and more particularly to a yarn-guiding traverse drum which is provided with a helical groove extending about and along the peripheral surface thereof, with mutually intersecting portions, for guiding a yarn passing therethrough so as to make it traverse back and forth along a cheese as the yarn is being wound on the cheese.

Generally, such traverse drums are made of metal, ceramic, glass or plastic. In view of easiness in molding or casting, metal and plastic are most widely used; and in view of strength, the former is more suitable than the latter. Among many different metals available for the purpose most suitable and widely used are aluminium alloys, which are light in weight, strong, and easy to be cast.

As is well known, the drum is provided with a yarn guiding-groove extending in a rather complicated curvilinear form about and along the drum surface, with different depths in different portions thereof. Therefore, in order that the drum can be cast to the required degree of accuracy, the molten alloy must have as good a fluidity as possible. Moreover, since the drum is rotated at a high speed in winding operation, centrifugal force is produced, which differs in magnitude in different portions of the drum due to the existence of the groove of complicated shape and different depths; and if the drum is heavy, the difference becomes so marked as to cause vibration of the rotating drum, which is of course undesirable. Therefore, the drum body must be as light as possible. Indeed, aluminium alloy can meet the requirement, but there is another problem to be solved, that is, surface hardness of the drum.

When as cheese is being wound, it has its outer surface resting against the cylindrical outer surface of the traverse drum by its own weight so as to be frictionally rotated thereby, with the yarn passing through the groove to be Wound onto the cheese in a traverse manner. It is seen that as the cheese is rotated by the rotating drum, a frictional contact occurs between the two surfaces, and the frictional force is great especially upon starting or stopping of rotation of the cheese. As a result, the peripheral surface of the drum is always subjected to wear. It is also seen that since the running speed of the yarn being wound onto the cheese is different from the circumferential speed of the inner surface of the groove the yarn is in contact with, the yarn slips thereon. This causes wear also to the inner surface of the groove. Therefore, the cylindrical outer surface of the drum as well as the inner surface of the groove must be as wearresistant as possible. Aluminium alloys, however, are not hard enough to withstand such wear. Therefore, the drum made of an aluminium alloy must be hard surfaced.

For hard surfacing of aluminum alloys, chrome plating may be employed. However, aluminium alloys tend to have their surface covered with an oxide layer, which makes direct plating of chromium thereon practically difficult. Therefore, the surface to be plated is first immersed in a Zinc bath to form a zinc layer thereon, which is then plated with chromium. This method, however, has

3,356,308 Patented Dec. 5, 1967 the disadvantage that it is practically impossible to effect a uniform deposit of plated chromium over the whole outer surface of the drum including the inner surface of the yarn-guiding groove. In other words, the plated chromium tends to build up on the peripheral surface of the drum and diminish therefrom towards the bottom surface of the groove. This is because chromium has a lower electrical resistance than zinc so that the chromium initially deposited on the peripheral surface of the drum tends to collect more chromium ions than the bottom surface of the groove, which is farther from the opposite electrode. Thus, the plating results in a thick deposit on the peripheral surface of the drum, and a very thin or no deposit on the inner surface of the groove, especially towards the bottom.

Instead of chrome plating, the drum surface may be hardened by forming a hard anodic coating thereon. This method can provide a uniform coating on the inner surface of the groove to the bottom as well as over the peripheral surface of the drum. This is because the anodized surface layer has a higher electrical resistance than the basic alloy so that formation of the layer on a portion of the drum surface, say, its peripheral surface, does not prevent anodizing of a different portion thereof, say, the bottom surface of the groove.

This method, however, involves another problem to be solved. In order to produce an effective anodic coating on the drum surface, the basic aluminium alloy must be within a certain limited compositional range, which in turn adversely affects casting of the drum. As previously mentioned, for accurate casting of the minute configuration of the groove on the drum, it is required that the molten alloy should have a good fluidity. To meet the requirement, the basic aluminium alloy must contain more than 7% by weight of silicon and more than 5% by weight of copper. On the other hand, for sufficiently hard anodic coating, the alloy must contain as small an amount of silicon and copper as possible; and with the above percentages of silicon and copper, it is practically impossible to produce hard anodic coating on the surface of aluminium alloys. Thus, accurate casting of the drum with its yarn-guiding groove and formation of an effective anodic coating go contradictory with respect to the amount of silicon and copper contained in aluminium alloys. If priority is given to the formation of hard anodic coating, the molten alloy cannot have a fluidity necessary to enable accurate casting of the drum, especially, the intersecting portions of the groove, so that machining and finishing work is required afterwards. For this reason, to the best knowledge of the present inventors, no traverse drum provided with a sufliciently hard anodic coating has ever been in practical use.

Accordingly, it is one object of the invention to provide a traverse drum having a yam-guiding groove for use in winding machines, which is cast of an aluminium alloy and provided with an anodic coating hard enough to long withstand the wear to which both the peripheral surface of the drum and the inner surface of the groove are subjected during winding operation.

Another object of the invention is to provide such a traverse drum as aforesaid, which is cast of an aluminium alloy having such compositions as to enable both accurate casting of the required configuration of the drum surface and at the same time formation of a sufliciently hard anodic coating.

Although the hard anodic coating is sufliciently hard and Wear-resistant for practical use, hard chrome coating can be more so. In addition, the chrome plating can provide a smoother surface for the cheese in sliding contact therewith, so that the yarn wound on the cheese is the lesslikely to be damaged. It may here be recalled thatthere is little difficulty in conducting hard chrome plating on the peripheral surface of the drum. Accordingly, a further object of the invention is to provide such a traverse drum as aforesaid, which has its peripheral surface with a hard chrome-plated coating and the inner surface of its groove formed with a hard anodic coating.

Other objects of the invention, its features and advantages will become apparent from the following detailed description with reference to the accompanying drawings, wherein:

FIG. 1 is a perspective view of the traverse drum of the invention;

FIG. 2 is an axial section of the drum, with its surface formed with a hard anodic coating; and

FIG. 3 is an axial section of the drum, having its peripheral surface plated with chromium and the inner surface of the groove formed with a hard anodic coating.

Referring to FIG. 1, there is shown a traverse drum 11 having a helical groove 12 extending about and along the peripheral surface of the drum. The drum 11 is cast of an aluminium alloy containing the following compositions in percent by weight: Cu, 1.0 to 5.0%; Si, 3.0 to 6.0%; and Fe, less than 1.2%.

As previously mentioned, the amount of silicon and copper contained in the aluminium alloy greatly affects the chemical and physical properties thereof. The greater the amount of silicon and copper contained in the alloy, the greater becomes the fluidity of the molten alloy; While the less the amount of silicon and copper, the greater is the hardness of the anodic coating formed thereon. If the amount of silicon contained in the alloy is taken along the abscissa While the fluidity of the molten alloy and the surface hardness of the anodic coating, along the ordinate, then the fluidity can be plotted as a curve rising towards the right, while the surface hardness, as a curve rising towards the left, with the two curves intersecting at a point where the amount of silicon contained is within the range of 3.0 to 6.0%. Experiments have disclosed that with an amount of silicon within the range, a satisfactory hardness of the anodic coating is attained, but the fluidity of the molten alloy is yet to be improved, Copper is added for such improvement. Addition of copper in an amount of 1.0 to 5.0% by weight of the alloy effects the fluidity thereof required for accurate casting of the drum of the required configuration without adversely affecting the hardness of the coating. If the copper added exceeds the above range, the properties of the alloy, especially its physical strength, are deteriorated. This must therefore be avoided.

Iron is added to give physical strength to the alloy. However, if the amount added exceeds 1.2%, iron segregates in the alloy. This must also be avoided. Impurities, such as magnesium, zinc, manganese, etc. that may well find their way into the alloy must be reduced to minimum.

An example of casting and subsequent surface treating of the drum will now be described. Molten aluminium alloy containing 2.0% by weight of copper, 5.0% by weight of silicon, 0.4% by weight of iron and traces of magnesium and manganese is put into a suitable mold to cast a required drum. After the casting solidifies, it is taken out of the mold and immersed in a dilute solution of sulfuric acid having a specific gravity of about 1.063 and being kept at a temperature of to 3 C. Then, with the drum as an anode, anodizing is performed by a current of A./dm. to form an anodic coating on the inner surface of the groove as well as the peripheral surface of the drum, as schematically shown at 13 in FIG. 2. 'It has been disclosed that the composition of the alloy provides a fluidity suflicient to enable accurate casting of the minute configuration of the groove and at the same time forms a uniform anodic coating of more than 850 H, in file hardness, the hardness being sufficient to withstand the wear the drum is normally subjected to in Winding operation.

In FIG. 3, the drum 11 is also made of an aluminium alloy within the above compositional range. In this case, the peripheral surface of the drum is plated with a hard chrome coating 14, while the inner surface of the helical yarn-guiding groove 12 is formed with a hard anodic coating 13 as in FIG. 2.

Before plating the peripheral surface of the drum, it is immersed in a zinc bath to form a zinc layer thereon, as previously mentioned. In this case, the inner surface of the groove may be covered with a suitable material, such as wax, so as to prevent chrome plating thereon. After the plating is completed, the wax is removed from the groove, and the chrome-plated peripheral surface of the drum is in its turn covered by wax. Then, the inner surface of the groove is anodized. Finally, the wax covering the peripheral surface of the drum is removed.

As previously mentioned, it is hard to plate with chrome the inner surface of the groove, especially towards the bottom thereof. Therefore, the inner surface of the groove may not be covered by wax. In such a case, the upper portions of the inner surface of the groove may well be plated with chrome. Then, the remaining uncoated portion of the groove surface is anodized.

In the above process, the chrome plating is performed prior to the anodizing. The order may be reversed, so that the inner surface of the groove is first anodized, With the peripheral surface of the drum having been covered with a suitable protective coating. Upon completion of the anodizing step, the protective coating is removed for chrome plating of that surface.

While preferred embodiments of the invention have been illustrated and described, it should be recognized that the invention is not limited thereto or thereby, and particularly that the method of producing the hard coating on the drum is not limited to those above described.

What we claim is:

1. A yarn-guiding traverse drum for use in winding machines, comprising a drum body having a peripheral surface for driving a package of yarn being wound and a yarn'guiding groove extending about and along said surface, said drum body being made of an aluminium alloy containing 1.0 to 5.0% by weight of copper and 3.0 to 6.0% by weight of silicon, and both said peripheral surface of the drum body and the inner surface of said groove being formed with a hard anodic coating.

2. A yarn-guiding traverse drum for use in winding machines, comprising a drum body having a peripheral surface for driving a package of yarn being wound and a yarn-guiding groove.extending about and along said surface, said drum body being made of an aluminium alloy containing 1.0 to 5.0% by weight of copper and 3.0 to 6.0% by weight of silicon, and said peripheral surface of the drum body being formed with a hard chrome plated coating, while the inner surface of said groove is formed With a hard anodic coating.

References Cited UNITED STATES PATENTS 3,080,134- 3/1963 England et al. 242-157 3,080,135 3/1963 Steijn 242-157 3,128,957 4/1964 Fallscheer 24243.2

STANLEY N. GILREATH, Primary Examiner. 

1. A YARN-GUIDING TRAVERSE DRUM FOR USE IN WINDING MACHINES, COMPRISING A DRUM BODY HAVING A PERIPHERAL SURFACE FOR DRIVING A PACKAGE OF YARN BEING WOUND AND A YARN-GUIDING GROOVE EXTENDING ABOUT AND ALONG SAID SURFACE, SAID DRUM BODY BEING MADE OF AN ALUMINIUM ALLOY CONTAINING 1.0 TO 5.0% BY WEIGHT OF COPPER AND 3.0 TO 6.0% BY WEIGHT OF SILICON, AND BOTH SAID PERIPHERAL SURFACE OF THE DRUM BODY AND THE INNER SURFACE OF SAID GROOVE BEING FORMED WITH A HARD ANODIC COATING. 